1. Field of the Invention
The present invention relates generally to integrated circuit fabrication equipment, and more particularly but not exclusively to magnetron sputtering.
2. Description of the Background Art
Magnetron sputtering, in general, is well known in the art of integrated circuit fabrication. A magnetron sputtering apparatus includes a target comprising a material to be deposited on a substrate. The substrate, which may be a semiconductor wafer, is located a distance away from the target. To coat the substrate with the target material, plasma of a gas suitable for sputtering is maintained between the target and the substrate. When ions of the sputtering gas hit the target, atoms of the target material are dislodged from the target and onto the substrate.
A target is considered a consumable item because it is eroded during the sputtering process. Unfortunately, a target is a relatively expensive component of a magnetron apparatus. Techniques for increasing the service life of a target are generally desirable because they help lower the cost of ownership of a magnetron apparatus.
It is also generally desirable to erode the entire surface of a sputtering target. If this does not occur, the locations on the target that are not eroded can accumulate, material sputtered from other areas of the target. Depending on the target material and sputtering conditions, this redeposited material can generate particles that can cause manufacturing defects in the wafers processed through the magnetron.